Flap Hinge. Requires a 35mm hole. This hinge is invisible from the outside & ensures a firm & precise fitting. Flap is locked in position when the hinge is turned through 90 degrees. Opened flap is flush with the base at a gap of 1mm. Universal mounting. The recess depth of the two hinge sections is 12mm. Has a covering rim to conceal the edge of the hole. Separate mounting of the base & the flap greatly simplifies installation and permits subsequent installation of lighter flaps. All metal - zinc alloy. Comes with screws. Nickel plated.